Plant and Animal Organ Systems and Their Functions

Immune System

• A complex network of different cellular actions and signals, allowing an organism to defend itself against a pathogen.

• It transmits information by chemical signals, or through the migration of cells.

• Dysfunction of the immune system can cause autoimmune disease , inflammatory diseases, allergies, and cancer. Immunodeficiency occurs when the immune system is less active than normal, resulting in recurring and life-threatening infections.

• Types of immunity

  • Innate and adaptive immune systems.

TYPES OF IMMUNITY

• Immune system categories

  • Innate and adaptive immune systems.

    • Innate Immune system is inherited

    • Adaptive Immune system is acquired

• Plant immune system

  • Plant protection mechanisms.

• Plant-pathogen interaction

  • Proteins and factors involved in plant defense.

• Future attacks preparation

  • Systemic acquired response in plants.

Preparing for Future Attacks

• Plant-pathogen interaction

  • Recognition receptors and immune responses in plants.

• Immune response in plants

  • Activation of defense genes and cell responses.

• Future attacks preparation

  • Systemic acquired response in plants.

  • The signals that induce SAR include salicylic acid

  • Jasmonic acid.

Plant Defense Response

• Plant defense responses

  • Gene-for-gene response and plant resistance.

• Plant immune response

  • Specifics of plant immune response compared to human immune response.

Animal Immunity

• Immune system function

  • Recognition of invaders by antigens.

• Animal immunity overview

  • Three lines of defense against pathogenic infection.

Facing a normal invader

• The immune system identifies harmful cells with nonself-antigens.

  • Immune cells release cytokines to communicate and respond to threats.

• When the skin is broken, immune cells respond to defend the body.

  • Natural killer cells attack invaders but may not eliminate all.

• Dendritic cells engulf invaders and mature into antigen-presenting cells.

  • B cells produce antibodies to stop bacteria, while T cells find abnormal virus fragments.

• APCs activate T cells by connecting through protein molecules.

  • Signal 1 (MHC connection) allows T cells to recognize antigens as threats.

  • Signal 2 (costimulatory signal) confirms the attack necessity.

• Fully activated T cells recognize and destroy invaders, multiplying to expand.

  • Some T cells become memory T cells for long-term immune protection.

• Regulatory T cells slow down the immune response once the threat is eliminated.

• Memory T cells can fight off the same invaders for months or years.

• Memory is crucial for immune protection against diseases like measles or chicken pox.